For a study, researchers sought to calculate the difference in the incidence of psoriasis (PsO) in children with inflammatory bowel disease (IBD), juvenile idiopathic arthritis (JIA), and chronic nonbacterial osteomyelitis (CNO) between the use of tumor necrosis factor inhibitor (TNFi) therapies and the presence or absence of conventional synthetic disease-modifying antirheumatic drugs (DMARDs).

From 2008 to 2020, a retrospective cohort analysis was conducted. Exposures to DMARD and TNFi were categorized as either always or never. The primary outcome was incident PsO. According to the underlying diagnosis, TNFi agent, and DMARD usage, PsO incidence rates (IRs) were segmented. To evaluate the IR ratios (IRRs) between exposure groups, Poisson regression was used.

The inclusion criteria were met by 5,088 children, of whom 3,794 (or 75% of them) had IBD, 1,189 (or 23% of them) had JIA, and 105 (or 2% of them) had CNO. Of the 2,023 kids who had been exposed to TNFi, 613 (30%) and 1,410 (70%) had DMARDs or did not have them. In patients exposed to adalimumab (ADA), the IRR of developing PsO was 2.70 times greater (95% CI 1.53-4.75; P<0.001) than in those who did not receive any TNFi medication, even when DMARD, sex, and family history of PsO were taken into account. Patients exposed to infliximab (IFX; IRR 2.34, 95% CI 1.56-3.51; P<0.001) and etanercept (ETN; IRR 2.21; 95% CI 1.17-4.21; P=0.006) had lower IRRs than TNFi-unexposed patients, although the differences were not statistically significant. DMARD-exposed patients had an IRR of TNFi exposure that was 0.25 lower than non-DMARD-exposed patients (P<0.001).

ADA, IFX, and ETN did not have significantly different IRRs for TNFi-induced PsO. However, the IRR was considerably lower in individuals who were additionally treated with a DMARD for those with exposure to any of the TNFi examined.